1. Field of the Invention
The present invention relates to a connector to which a thin plate-like connecting object such as an FPC or FFC, etc., is to be connected.
2. Description of Related Art
A connector via which a circuit board (rigid board) and a thin plate-like (thin sheet or thin plate) connecting object (e.g., an FPC or FFC, etc.) are electrically connected is usually provided with an insulator and a plurality of contacts. The insulator is provided with a groove into which the connecting object is insertable, and from which the connecting object is removable, and a plurality of contact insertion grooves which are elongated in the connecting object insertion/removal direction and arranged in a direction orthogonal to the connecting object insertion/removal direction, and the plurality of contacts are inserted into the plurality of contact insertion grooves of the insulator, respectively. The plurality of contacts are connected to conductor traces of a circuit pattern formed on a surface of the circuit board. Upon the connecting object being inserted into the aforementioned groove of the insulator, the connecting object comes into contact with each of the aforementioned plurality of contacts, so that the circuit board and the connecting object are electrically connected to each other via the plurality of contacts.
Such a conventional connector is disclosed in Japanese Patent Publication No. 4,413,961.
To improve the high frequency property of an electrical signal fed to this type of connector (the contacts thereof), it is required to make the impedance (value) of the connector as close to the impedance (value) of the circuit board and the connecting object as possible.
However, the insulator is provided with partition walls which are formed between the plurality of contact insertion grooves so that each partition wall separates the adjacent contact insertion grooves from each other, and the relative permittivity of the synthetic resin which forms the insulator is usually high (e.g., approximately three to four). Accordingly, such a conventional type of connector has a structure in which the coupling capacitance between adjacent contacts easily increases, and the impedance (value) of the connector tends to decrease largely as compared with the impedance (value) of the circuit board and the connecting object.